The disclosure relates to an abnormality determination device and an abnormality determination method that make an abnormality determination of a lock up clutch in a vehicle including an automatic transmission having a torque converter.
An automatic transmission in a vehicle, e.g., an automobile, generally includes a torque converter having a lock up clutch. Controlling operation of the lock up clutch causes a rotating member on input side, e.g., a pump impeller, and a rotating member on output side, e.g., a turbine runner, of the torque converter to be set at an engaged state or a disengaged state. Setting the engaged state in accordance with traveling situations of the vehicle makes it possible to attain, for example, enhancement in transmission efficiency of motive power to be transmitted from an engine to the automatic transmission, and enhancement in fuel consumption performance in the vehicle.
In such a lock up clutch, there occurs a case of an abnormality in which, for example, the lock up clutch becomes stuck in the engaged state as mentioned above. Accordingly, inside vehicles, in general, a determination, detection, and/or diagnosis of such an abnormality are made at any time. For example, reference can be made to Japanese Unexamined Patent Application Publication (JP-A) Nos. H02-176265 and H11-280893.